Assuming you weren't riding at full throttle for that tank full...is it possible you had "bad" fuel on that fill-up? Not sure if you get to ENJOY seasonal blended fuel in the UK, but that can result in reduced mileage. Try changing to another branded fuel on your next fueling and let us know how that works out.

At the risk of opening a can of worms, I'm only getting around 30mpg equivalent around the suburbs on my GRiSO. Improves to around 37-40mpg on the highway. I've had the lambda disabled and had the idle mixture trimmer adjusted to make it richer across the range, as I had bad problems with surging, backfiring and popping with my Termignoni exhaust. Throttle bodies have been balanced by somebody I trust.

I realise the more permanent fix is to get a customised fuel map, but I haven't got around to doing that yet. I get around 200kms (125 miles) from a full tank until the fuel warning light comes on.

I get around 135 miles before the low fuel light with a mix of highway (high speed) and doping around town. I have a Termi and I am running a Beetle Map designed for it. Brent, just do it! You won't regret it.

I too have a beetle Map, that is currently residing on my PC until the weather got warmer, maybe now is the time to re-install, but i went most of last year without this mileage, maybe i am bucking the trend and getting faster in my old age!!

i had problems with shitty fuel got that sorted and rebooted the ecu and while it was relearning saw 4.3l/100kms it fluctuated a bit even saw 7.1l/100kms seems to have settled down to 5.4l/100 been fairly constant smooth running no surging or rough running i'm happy i'm using 98 octane premium fuel.

Mine does about 25 MPG around town as well. Stock everything. 93 Octane 10% Ethanol fuel (Fuck you, Texas gasoline). Highway mileage is more like 40-42 but around town it is a thirsty girl.

I've actually been looking into if there was anything I can do to improve that. People keep talking about Beetle maps- I'm assuming Beetle is the guy Beetle, yeah? Are the ECUs on a GRiSO remapped-able or do you have to run some sort of replacement or piggy-back ECU to remap?

I ran out of fuel yesterday, on the way to the gas station. Tank took 16.65 liters according to the pump, 280 km of spirited riding. Works out at 5.95 l/100km, dashboard was showing average of 4.2 l/100km. I know now to ignore that!

I've actually been looking into if there was anything I can do to improve that. People keep talking about Beetle maps- I'm assuming Beetle is the guy Beetle, yeah? Are the ECUs on a GRiSO remapped-able or do you have to run some sort of replacement or piggy-back ECU to remap?

I am that Beetle guy. The 5AM ECU is easily remapped. No evil piggy back black boxes required.

Cold weather has me about 10% lower mileage, probably because I changed the trim from -3 to 0 for better fueling. Still seeing 30's on the commute and 40's on the highway. I also put ethanol treatment in at every fill-up and that seems to help both economy and running.

Mine does about 250km before the reserve light goes on. Since refueling costs just about 30€, that's almost 1€ per 8km. Not sure how that compares to other countries but I'm sure its on the expensive side.

Is it because your fuel is so expensive that you all check it? Have never checked mileage on a bike. When it needs fuel I stop and fill it up.

Funny you say that- I've never owned a bike that got mileage low enough for me to notice. I remember vividly my first day on the GRiSO, I was running around town , staying off the highways and riding it spirited (but not too spirited) to vary RPMs and whatnot and my damn fuel light came on at 85 miles on the odometer. Took on a full tank of gas. I was shocked and had a "Oh god, Oh god, what have I done?!" moment. Turns out on the highways it's not so bad, but around town, yeah ... the only reason I noticed is because it was so dramatically low compared to what I was accustomed to.

Mine does about 250km before the reserve light goes on. Since refueling costs just about 30€, that's almost 1€ per 8km. Not sure how that compares to other countries but I'm sure its on the expensive side.

Pre Beetle map I was getting 5.5 kms/100kms now I an 4.8/4.9. To me that is amazing for an 1100, esp considering I am circa 230 pounds and have a heavy right wrist. My previous GRiSO 850 went from 5.5 to 4.7 with the Bettle map.

I ran out of fuel yesterday, on the way to the gas station. Tank took 16.65 liters according to the pump, 280 km of spirited riding. Works out at 5.95 l/100km, dashboard was showing average of 4.2 l/100km. I know now to ignore that!

My theory is that the fuel calculator can't keep up with spirited riding.

Gotta agree with you, there is no other explanation I can come with. Those with power commanders installed (I have them on other bikes) are particularly vulnerable, as the Dash/ECU has not idea what the power commander is contributing.